Method of manufacture of artificial silk



1,621,590 March 1927' c. c. JESSEN METHOD OF MANUFACTURE OF ARTIFICIALSILK Filed March 20. 1925 3140c nto'c CHARLES (Z Jqssgm,

Patented Mar. 22, 1927 1,621,590 PATENT OFFICE,

CHARLEB C. JESSEN, OI WILIINGTQN, DELAWARE, A SSIGNOB TO ATLAS POWDERCOMPANY, OI WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE.

mrrnon or MANUFACTURE. or ARTIFICIAL smx.

Application and March 2c, 1925. Serial in. 17.133.

x This invention relates to a step in the manufacture of artificial silkand it has for its object to provide means for imparting uniform tensionto the silk during its 5 manufacture with the result that a greatly imroved product is secured, I

n the manufacture of artificial silk by the copper ammonium process,using what is known as the wet twist or ot twisting 1 method, aplurality of stran s from the spinnerets are passed, in parallelism,through a centrally disposed guide tube to the interior of a rapidlywhirling pot or centrifuge and the several strands are twisted V into athread by the action of this pot in carrying. the thread around the axisconstituted by the guide tube. This is the common and well knownpractice and forms no art of the present invention. The thread 'uildsup. on the inside .ofthe centrifuge in" the form. of a cake and when asufiicient amount has been collected in the centrifuge it is removed,still in the form of a cake and the thread is withdrawn from said cakeand wound upon a rotating cylinder or bobbin,

which may or may not run in a decopperiz- 1% bath. The thread isthereafter dried w lle still mounted upon the cylinder or bobbin. Moretension is imparted to the silk during the beginning of the spinningoperation in the centrifuge than toward the end thereof, or at the timewhen the pot has been sufiiciently filled and the cake is to becentrifugal force is greater when the pot is empty and such centrifugalforce is exerted the entire distance between the guide tube trifugalforce at different periods of the filling of the centrifuge,- bthereafter winding and drying the threa s upon a cylinder o'r-bobbinofsuch determinate size with respect to the size of the centrifuge as toexert a compensating tension upon the threads.

In the accompanying drawing, Fig. 1 is a view artly' in sectionand artlyin side elevation of one of thebobbins' hereinafter u described and Fig;2 isa sect onal view of removed. This arises from the fact that the,

imparted thereto, by centrifugalforce, will be the part that will bewound upon the operation; As the thread builds up upon the one of thecentrifuge pots. In the drawing,

5 designates one of the centrifuge pots,

which is, under the usual practice, rotated at a high rate of speedduring the time that a plurality of threads in' parallelism are beingfed through the guide tube 5. The threads are twisted ihto a unitarystrand about the axis of the tube 5' by the whirling action of thecentrifuge pot. It is manifest that when the cake of the thread beginsto build. up in the pot, as indicated in Fig. 2, the tension upon thereach of the threads extending between the lower end of the tube and theside of the'ppt, is greatest and that this tension orfstrength graduallydecreases as the cake builds up toward the center of the pot. Afterthecake has been built up to the desired size, it is removed from thepot and the 'thread is withdrawn from the outside of the cake, passedover any suitable guide,*such as a" hook 7, and is wound upon a: s l orbobbin 8, under the influence o a traverse arm 9. The means for re tingthe bobbin and for actuating the trave se arm form no part ofthe-present invention. It is common practice to wind thread u n a bobbindirectly from the cake an over a suitableguide means, such a structurebeing 1llustrated in my co-pending application, Serial Number 749,093,filed on t e 10th day of November, 1924. As before stated, thread thatis to be wound on the bobbin is withdrawn from the outside of the cake.As the cylinder or bobbin becomes filled, it will, in effect, have anincreased diameter. Thus, that part of the thread which is the first toenter the centrifuge or pot and which has the greatest stress mycylinder at the beginning of the winding cylinder the effective diameterof the. cylinder is increased and the speed of travel of the thread overguide 7 and consequently the pull upon the thread, b said guid'eilislikewise increased, Thus t e t at was the lastto enterthe centrifugewhich consequentl the least will be'the part ts'lwill receive the-moststress in beingwound upon the cylinder.

Thus, in the winding upon theeylinder' or bobbin, I compensate'for oftenn and the centrifuge pot in proper propornot occurring, swing thewindinga'uniform tensionjori'stietch at all points-in achieved by havingthe cylinder or bobbin tions with relation to each other. One=proportion which I have found to give thedesired results,is-as'follows. -Where the outside diameter of the cake is four and one.-

- half inches. 1 use a bobbinof three and one-half inches in diameterand of such length as to produce about the same. length I is dried onthe cylinder or bobbin, that partofthe thread which receives the moststress the twisting pot receives the least or none of thread traverse onthe bobbin asfwas traversed in makin .the cake. The result :of this isto build t e thread on the bobbin in such, form that its finisheddiameter is to see other it follows that when the thread at all, duringthe drying process on the cylinder and that the threads receiving the-least or minimum stress in the pot receive the maximum stretch orstrain during such drying period. In other words, a secondary,compensatory stretching action takes place during-the drying period,that is in addition to the compensatlng action that takes place duringthewinding upon the bobbin. This is due to the fact that after thethread is washed while wound on. the bobbin, as is the commonractice,-it is in a more or less.

swollen con ition. In other words, the thread is more swollen when wetthan when in the acid condition. This swelling of the wet thread has theefiect of further stretch-- ing the outer layersof thread on the bobbin.The d ing takes place vfrom the. outside and driest e thread undertension, which ten-.

sion decreases asthe bobbin of thread dries on downto the bobbin itself.

The net result of the 'whole operation is that stretches or strains inthe individual fibers or filaments are equalized throughout thecompletelength of the threads, so made. This is of a very great'imortance because it results in producing a t read that is of a uniformhardness and strength so that when it is woven into an artificial silkcloth all parts of the cloth will absorb d e to the sameextent andthuh'produce an a solutely uniform color; The production of e. um-

v in l the centrifuge pot andproduce a three; having form color indyeing of goods of this sort is notfpossible whencone Having describedmy invention what I claim is:

a 1. The herein described step in the manua cake upon a cylinder andfrom the outside rt of the clothis v p I v A of a different texturefr'oih another. its length. The" foregoing results "are of said cake,said cylinder being of such proportion, with respect to the diameter ofthe cake, that as the thread is wound upon the cylinder those portionsof the thread which were subjected to the greatest tensiomby centrifugalforce in the centrifuge, will be subjected to the least tension duringsuch winding and those portions of the thread which were subjected tothe least tension in the centrifuge will be subjected to the greatesttension during winding.

2. That step in the production of artificial silk which consists of theemployment of a centrifuge pot of such proportion with respect to thewinding cylinder or bobbinas to produce a uniform tension u on thefinished product when the three] is wound upon said bobbin from theoutside of the cake pioducedin the centrifuge Pet.

3. at step in the manufacture of artificial silk which consists ofwinding the thread from the outside of a cake produced in a centrifugepot, over a guide and upon a bobbin of such diameter, with respect tothe centrifuge pot, as to equalize the nonproportion, with respect tothe diameter of the cake, that when the thread is dried upon thecylinder those portions of the thread which were subjected to thegreatest tension, by centrifugal force in the centrifuge,-will besubjected to the least tension during such drying and those portions ofthe thread which were subjected to the least tension in the centrifugewill be subjected to the greatest tension during drying.

In testimony whereof he afiixes his signature.

' CHARLES C. JESSEN.

